When we are looking at distant starts and galaxies, some are as far as 5 billion light years away. So that means that it takes 5 billion years for light to get to us. But once the light does get to us, how come it I can still see it some time later.
If I look through a telescope and see light from a dead star now, which is maybe 1 billion light years away, does the fact that I can see that light means that it had reached me? If it has already reached me, and the star is dead, why doesn't the light just keeps going past me.
Im not sure if my question is clear, but Im always imagining that once the light source is finished, the light should cease to exist as well. Yet we can continue to look at light coming from dead stars.
Thanks